Previously, we described a direct inhibitory effect of sodium artesunate on sodium chloride transport in the thick ascending limb of Henle's loop, indicating that artesunate acts as a diuretic agent. Here we present 2 cases of falciparum malaria treated with 4 intravenous 60-mg doses of sodium artesunate. Neither diuretics nor vasoactive drugs were administered. A rise in diuresis (6 L/24 hours) was accompanied by an increase in natriuresis, and both declined at the end of the treatment. This diuretic effect has not been reported previously in patients and may modify the course of renal failure and respiratory distress syndrome, both of which complicate severe malaria.